Process for producing refractory compounds



I No Drawing.

To all whomz'tmayconcem:

wrnrannm. HANDY, or sronn, wasnmc'ron.

PROCESS FOR PBODUGIN'G REFRAC'EORY' COMPOUNDS."

' which the fol owing is a specification.

The present invention relates to an improved process of producing a refractory composition, the composition being especially intended for a refractory material, and the process being carried out in the operation of forming a lining for the interior walls of a furnace, by the heat from the furnace.

The primary object of the invention is the provision of a process of manufacturing a refractory material especiallyadapted for a furnace lining at a com aratively low cost of roduction, and in w ich there is a very hig quality of cementation and self bond ing, thus providing a refractory material especially fitted for the 1purpose of lining he invention contemplates a composition which is laid on or plastered against the walls of a furnace while in a pulverized and moistened, or

'0 plastic condition which will set as a cement,

and-then under thesubsequent action of an intense heat in the furnace will vitrify' into 'a dense, homogeneous mass of a basic na ture, especially adapted as a lining for furnaces to resist thecorrosive action of molten metalaslags and gases. 4

Hereinafter Ihave set forth one complete example of the ph sical embodiment of the invention, with as ight variation or modification thereof, in which the best/modes for the practical applications of the principles of the invention .are set forth, and which have proven highly satisfactory and successin actual practice. En carrying out the process of manufacturmg the composition I utilize as the essen-.

tial com onents or ingredients magnesia iron om and silica, and while l have use these ingredients in varying proportions,

tit)

one specific formula as used may be set forth as. follows:

. A composition of this formula and. in substantially this proportion is especially in the process of mixin Specification-oi Letters Patent. Patented Feb. 10, 1920. Application filed June 3,1918. Serial No. 237,970.

suitable for lining certain metallurgical furnaces, such as are employed in the production of steel, copper, etc.

I have discovered that a compound of iron oxid with an acid radical, such as iron carbonate, iron sulfate, iron chlorid, etc., when heated in contact With ma esium oxid, will unite and form a dense an strong compound of the desired proportions of iron and magnesia. I prefer to take calcined magnesia low in iron, owder it, and then mix with it the iron su fate, eitherin solution, or in solid form, andthis moistened I mixture will quickly set to a-fairly strong cement. It is very essential that the struc ture of the lining composition be uniform,

inasmuch as its fusibility varies greatly with I the iron content, the fusion point rapidly lowering as the iron increases, while if the iron content is very low, the composition becomes very friable and is subject to rapid disintes gration. This uniformity'of the structure may be attained with facility and accuracy the ingredients, and it is therefore poss1 le to apply this mixture in the form of a cement, to the interior wal s of the furnace to be lined, allow the coating or lining to set, and then fire up the furnace and thus sinter the lining into place by the heat from the furnace.

I have also found it possible to spread out a layer of calcined magnesia u on a tight floor, and pour over it a su cient quantity 'of iron sulfate to give any iron content desired. 1 This mixture, if allowed to stand and dry will harden to a solid crust which may then be broken up in small pieces, andca cined in any of the usual ways, the temperature required being from 2800 to 3000 degreesl Y a if desired, the composition may be made into bricjuets after having been either sintered in loose form in a rotary kiln to a hard clinker, or made into briquets, allowed to set and harden, and then stacked in a brick kiln and there burned at a high temperature for several days, or, the hardened briquet may be sintered in'a'n upright kiln, either by feeding the fuel in solid form with the charge, or by firing through fire boxes orvents near the base of the kiln;

In some instances iron carbonate or iron sulfid may be used in place of the sulfate or other compound of iron with equally good results as far as the production of a ferret laster or plastic 4 magnesite is concerned, but this I mixture does not have the good cementing proper-- combine to form a good ferro-magnesite,-

which however does not produce as moxpensive a product as is secured by using the iron salt. Silica afl'ects the fusibility slightly, but greatly aids in forming a stronger and tougher composition, but an excess of silica is objectionable because of its tendency to increase slag; losses. Few

deposits of natural magnesium minerals po's-l sess sufiicient proportions oi these substances when calcined, and in the few which do approach the desired compound in composition, the proportion of iron is extremely va riable, and it is diflicult to produce from such material furnace linings with a uniform composition and dependable qualities.

The immense deposits of crystalline magnesite in Stevens county, Washington, contain silica very uniformly distributed in proportions especially. suitable for the highest grade refractories, but the iron content is uniformly low, generally averaging about three per cent. in the calcined substance. There needs to be added but 4 to 6 per cent. of iron oxid to produce the ideal refractory.

I claim The process of making a basic refractory material which consists in pulverizing and mixing calcined magne'site, iron compound and silica, and calcining the mixture in a kiln, to cause the oxids of magnesium and iron to unite.

In testimony whereof I afiix my signature.-

' WILFRED M. HANDY. 

